Expansion coal cutter



May 13 ,.1924.

J c; MORGAN EXPANSION COAL CUTTER Filed Aug. 2 1921 m m a Patented May 13, 1924.

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PATENT EXPANSION COAL CUTTER.

Application filed August 2, 1921. Serial No. 489,169.

T all whom it may concern:

Be it known that I, JAMES G. MORGAN, a citizen of the United States, residing at Wilkes-Barre, in the county of Luzerne and State of Pennsylvania, have invented certain new and useful Improvements in an Expansion Coal Cutter; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

In mining operations, and more particularly in the mining of coal, it is desirable to enlarge the inner portion of the opening formed by drilling into the vein or stratum of coal for receiving the explosive charge.

This invention provides a drill which is expansible, so that the outer. end of the bore may be of smaller diameter than the inner end, said drill being self expanding to a determinate extent.

Other objects and advantages will be apparent and suggest themselves as the nature of the invention is understood.

While the drawing illustrates an embodimentof the invention it is to be understood that in adapting the same to meet difierent conditions and requirements, various changes in the form, proportion and minor details of construction may be resorted to without departing from the nature of the invention.

Referring to the accompanying drawing forming a part of the specification,

Figure 1 is an elevation of a drill illustrative of the invention showing the bit in contracted position.

Figure 2 is a view similar to Figure 1, the bit being expanded and a portion of the head broken away.

Figure 3 is a side view of the drill, and

Figure 4 is a horizontal section on the line yy of Figure 1.

Corresponding and like parts are referred to in the following description and designated in the several views of the drawing by like reference characters.

The drill comprises a head 1 provided with astem 2 said head'being slotted at its outer end as indicated at 3. Similar bits 4 are pivotally connected to the head 1, as indicated at 5, and have their pivotal ends overlapped and fitted in the slot 3 of the head 1. The bits 4 consist of elongated blades. The rear (1 of each bit is straight and the forward or cutting edge 6 is curved and notched. Each of the bits a has a short straight cutting edge 0 at its outer end. The cutting edges 6 and 0 are curved laterally as indicated most clearly in Figures 3 and e. The pivot fastenings 5 may consist of bolts, machine screws or other fastening means. Each of the bits 4 has an opening 6 and these openings are so disposed as to register when the bits are in contracted position, as indicated in Figure 1. A pin 7 extends through the registering openings 6 to hold the bits 4: in contracted position. When the pin 7 is removed the bits at are free to expand substantially as indicated in Figure 2.

Each of the bits has a notch 8 in its outer or rear edge to provide clearance for the respective pivots 5 when the bits are ex panded, as shown most clearly in Figure 2. In addition each bit has a stud 9 projecting laterally therefrom to form a stop or limit the expansion of the bits, Figure 2. A lug 10 at the outer or rear edge of one of the bits is adapted to engage the inner or forward edge of the companion bit and limit the closing of the bits. This is indicated in Figure 1. The studs 9 project outwardly from the respective bits.

In the initial operation of the drill the bits 4 are in contracted position and after the opening has reached the desired depth the drill is withdrawn and the pin 7 removed and upon replacing the drill in the bore and continuing the drilling operation, the bits 4 expand and the resultant opening is of larger diameter accordin to the spread or expansion of the bits. t is observed that the bits expand automatically and contract in a like manner to admit of withdrawing the drill from the opening.

Having thus described the invention, what I claim is 1. A coal drill of the character specified, comp-rising a head, elongated blades disposed in overlapping relation and having their inner ends independently pivoted to the head, and having their outer ends forming short straight cutting edges, their rear edges straight and their forward edges curved, sharpened and outwardly deflected, studs projecting outwardly from the sides of the blades to engage the head and limit the expanding of the blades, and means carried by one of the blades to engage the gage the head and one of the bits having 10 a stud to engage the companion bit.

In testimony whereof I affix my signature in presence of two Witnesses.

JAMES G. MORGAN. Witnesses:

ROBERT CHALLIS, J12, RICHARD Rooms. 

